The present invention relates to improvements in drives such as for controlled deflection rolls for papermaking machines or the like, and more particularly to an improved controlled crown roll drive where the input power is coaxial with the roll shell through a planetary gearing.
Controlled deflection rolls are used commercially in various environments such as in papermaking machines, textile machines and other industries where a long roll has to sustain a load and have a controlled deflection. One area of use is in a papermaking machine wherein such a roll may be used in a calender stack or press section and forms a paper web processing nip with another roll. The controlled deflection roll is operated so that it maintains a nip of uniform or controlled nonuniform pressure along its nip formed with another roll. Such controlled deflection rolls commonly have a roll shell which is rotatable on a stationary shaft and a fluid force transmitting means is located between the roll shell and shaft so that the shell is supported uniformly along its length by the fluid force transmitting means. In control of the deflection of the roll, the pressure in the fluid is controlled to match the opposing roll to obtain the desired nip force per unit of roll shell length between the controlled deflection roll and the opposing roll. An example of such a roll is in the Justus U.S. Pat. No. 3,276,102.
In such controlled deflection rolls, the roll shell often must be driven to carry the material being processed through the nip. In driving such commercial rolls, high horsepower requirements are encountered and these driving forces must be transmitted from a drive to a roll shell which bends in varying amounts during operation thereby tending to misalign the drive which cannot be tolerated at high drive loads. Means have been provided heretofore to accommodate such bending, but these structures have often been complex and space consuming.
With the horsepower requirements for huge papermaking machines, the use of planetary gearings is advantageous in such gearings' capability of carrying high horsepower loads. Another requirement for a drive is that it require a minimum amount of space, and in papermaking machines with a large number of drives with the various sections of the machine, a drive which is coaxial with the roll is advantageous.
Various attempts at improved drives have been made, and examples of drives for controlled crown rolls of papermaking machines are shown in U.S. Pat. Nos. 3,639,956, 3,766,620 and 3,889,334.
An object of the invention is to provide an improved drive for a paper machine controlled deflection roll or the like utilizing planetary gearing wherein the loads between the sun gear and the planetary gears are automatically equalized to accommodate misalignment or imperfections in manufacturing.
A further object of the invention is to provide an improved drive for a roll wherein the drive requires less space and can be located coaxial with the roll.
A further advantage of the invention is to provide an overall improved drive for a roll shell capable of handling substantially large power inputs.